Terai Kazuto, Sano Yoichiro, Kawasaki Satoshi, Endo Ken-ichi, Adachi Wakako, Hiratsuka Takeaki, Ihiboshi Hirotoshi, Nakazato Masamitsu, Kinoshita Shigeru
Department of Ophthalmology, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto 602-084, Japan.
Exp Eye Res. 2004 Aug;79(2):175-80. doi: 10.1016/j.exer.2004.03.006.
Human beta-defensins (hBDs), which are mainly expressed in epithelial tissues, may contribute to infection-protective mechanisms in the ocular surface. We examined hBD1 and hBD2 expression in the ocular surface by RT-PCR and immunohistochemistry and studied the effects of immunosuppressive agents on their expression in human corneal epithelial cells in vitro. mRNA expression of hBD1 and hBD2 was confirmed in corneal epithelial cells. While the hBD1 peptide was immunohistochemically detected in corneal, limbal, and conjunctival epithelium, the level of expression was stronger in limbal- and conjunctival- than in corneal epithelium. Very weak expression of the hBD2 peptide was detected only in corneal epithelium. After 48-h culture of human corneal epithelial cells in the presence of 10(-5) M dexamethasone or 1 mg l(-1) cyclosporin A, total RNA was extracted and hBD1 and hBD2 mRNA expressions compared using semi-quantitative RT-PCR and introduced amplified fragment length polymorphism (iAFLP) assay. The two methods yielded almost identical results. hBD1 mRNA expression was not changed by dexamethasone but was down-regulated by cyclosporin A. hBD2 mRNA expression was up-regulated by dexamethasone and down-regulated by cyclosporin A. Our findings suggest that hBD1 and hBD2 are regulated by different mechanisms and that hBD1 may contribute to infection-protective mechanisms in the relatively immunosuppressed status induced by dexamethasone.
人β-防御素（hBDs）主要在上皮组织中表达，可能有助于眼表的感染防御机制。我们通过逆转录聚合酶链反应（RT-PCR）和免疫组织化学检测了眼表中hBD1和hBD2的表达，并在体外研究了免疫抑制剂对人角膜上皮细胞中它们表达的影响。在角膜上皮细胞中证实了hBD1和hBD2的mRNA表达。虽然在角膜、角膜缘和结膜上皮中通过免疫组织化学检测到了hBD1肽，但角膜缘和结膜上皮中的表达水平比角膜上皮中的更强。仅在角膜上皮中检测到hBD2肽的非常微弱的表达。在10^(-5) M地塞米松或1 mg l^(-1)环孢素A存在的情况下对人角膜上皮细胞进行48小时培养后，提取总RNA，并使用半定量RT-PCR和引入的扩增片段长度多态性（iAFLP）分析比较hBD1和hBD2 mRNA的表达。这两种方法产生了几乎相同的结果。hBD1 mRNA的表达不受地塞米松的影响，但被环孢素A下调。hBD2 mRNA的表达被地塞米松上调，被环孢素A下调。我们的研究结果表明，hBD1和hBD2受不同机制调控，并且hBD1可能在由地塞米松诱导的相对免疫抑制状态下有助于感染防御机制。
